Various communication systems, such as microwave links, transfer data at variable data rates. For example, U.S. Patent Application Publication 2005/0075078, whose disclosure is incorporated herein by reference, describes a method for transmitting signals via a point-to-point microwave radio link. In order to improve the efficiency on the radio link, transmitted packets are classified before transmission based on quality of service parameters assigned to each packet. The signals are modulated for transmission using a real-time adaptive modulation. The modulation is adapted based on the current traffic amount, signal quality measurements indicative of the propagation conditions on the radio link, and the classification of packets comprised in the signals.
Some communication systems increase the transmission reliability by using protected configurations of two or more communication links in parallel. For example, Ericsson LM (Kista, Sweden) offers a microwave link product line called MINI-LINK, which supports such protected configurations. Further details regarding this product are available in www.ericsson.com/products/hp/MINI_LINK_pa.shtml.